Environmental impacts of large dams environmental sciences essay

Between anda team led by H. Dozens, then hundreds of people were sent by helicopter and seaplanes in inaccessible areas of the taiga to perform surveys and geological studies to identify potential sites for hydropower development.

Max Gerber] I am often asked whether I agree with the new group selectionists, and the questioners are always surprised when I say I do not. After all, group selection sounds like a reasonable extension of evolutionary theory and a plausible explanation of the social nature of humans.

Also, the group selectionists tend to declare victory, and write as if their theory has already superseded a narrow, reductionist dogma that selection acts only at the level of genes. The more carefully you think about group selection, the less sense it makes, and the more poorly it fits the facts of human psychology and history.

The problem is that it also obfuscates evolutionary theory by blurring genes, individuals, and groups as equivalent levels in a hierarchy of selectional units; Most importantly, it has placed blinkers on psychological understanding by seducing many people into simply equating morality and culture with group selection, oblivious to alternatives that are theoretically deeper and empirically more realistic.

Does this mean that the human brain has been shaped by natural selection to promote the welfare of the group in competition with other groups, even when it damages the welfare of the person and his or her kin?

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If so, does the theory of natural selection have to be revamped to designate "groups" as units of selection, analogous to the role played in the theory by genes? Several scientists whom I greatly respect have said so in prominent places.

And they have gone on to use the theory of group selection to make eye-opening claims about the human condition. Wilson explains, "In a group, selfish individuals beat altruistic individuals.

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But, groups of altruistic individuals beat groups of selfish individuals. They suggest that evolution has equipped humans to solve tragedies of the commons also known as collective action dilemmas and public goods gamesin which actions that benefit the individual may harm the community; familiar examples include overfishing, highway congestion, tax evasion, and carbon emissions.

And they have drawn normative moral and political conclusions from these scientific beliefs, such as that we should recognize the wisdom behind conservative values, like religiosity, patriotism, and puritanism, and that we should valorize a communitarian loyalty and sacrifice for the good of the group over an every-man-for-himself individualism.

I am often asked whether I agree with the new group selectionists, and the questioners are always surprised when I say I do not. Why does this matter? The first big problem with group selection is that the term itself sows so much confusion.

People invoke it to refer to many distinct phenomena, so casual users may literally not know what they are talking about.

I have seen "group selection" used as a loose synonym for the evolution of organisms that live in groups, and for any competition among groups, such as human warfare. Sometimes the term is needlessly used to refer to an individual trait that happens to be shared by the members of a group; as the evolutionary biologist George Williams noted,"a fleet herd of deer" is really just a herd of fleet deer.

And sometimes the term is used as a way of redescribing the conventional gene-level theory of natural selection in different words: For this reason, the theory is often called "multilevel selection" rather than "group selection.

No one denies that such faculties exist. Group selection as an explanation of the traits of groups. The core of natural selection is that when replicators arise and make copies of themselves, 1 their numbers will tend, under ideal conditions, to increase exponentially; 2 they will necessarily compete for finite resources; 3 some will undergo random copying errors "random" in the sense that they do not anticipate their effects in the current environment ; and 4 whichever copying errors happen to increase the rate of replication will accumulate in a lineage and predominate in the population.

After many generations of replication, the replicators will show the appearance of design for effective replication, while in reality they have just accumulated the copying errors that had successful replication as their effect.

The copying errors mutations are random more accurately, blind to their effects. The outcome of interest is the number of copies in a finite population. The surprising outcome is a product of the cumulative effects of many generations of replication.

If the copying errors were not random that is, if Lamarck had been correct that changes in an organism arise in response to a felt need, or if creationists were right that a superior intelligence directed mutations to be beneficial to the organismthen natural selection would be otiose—the design could come from the mutation stage.

If the outcome of interest were not the number of copies in a finite population, but some human-centered criterion of success power, preeminence, influence, beautythen natural selection would not be mechanistic: And if it took place in a single generation, then natural selection would be banal, since it would add nothing to ordinary physical cause and effect.

When a river erodes the soft rock layers on its bed and leaves behind the harder layers, or when the more volatile compounds in petroleum evaporate faster than the less volatile ones, one hardly needs to invoke the theory of natural selection. One can just say that some things are stronger, or longer-lasting, or more stable than others.

Only when selection operates over multiple generations of replication, yielding a cumulative result that was not obvious from cause and effect applying to a single event, does the concept of natural selection add anything.

The theory of natural selection applies most readily to genes because they have the right stuff to drive selection, namely making high-fidelity copies of themselves. Nor can any organism, sexual or asexual, pass onto its offspring the traits it has acquired in its lifetime.

Individual bodies are simply not passed down through the generations the way that genes are. But its explanatory power, it seems to me, is so distinctive and important that it should not be diluted by metaphorical, poetic, fuzzy, or allusive extensions that only serve to obscure how profound the genuine version of the mechanism really is.

To be sure, some extensions of natural selection to replicators other than genes are rigorous and illuminating, because they preserve the essential features of replicator dynamics.

Examples include bits of code in genetic algorithms, the analogs of genes in artificial-life simulations, and, if the physicist Lee Smolin is correct, the laws and constants of entire universes.

But other extensions are so poetical that they shed no light on the phenomenon and only obscure the real power of natural selection. Cities have more old buildings made of stone than of wood because of the process of edifice selection. Cars today are equipped with steel-belted radials because they outcompeted polyester-belted tires in a process of tire selection.A newly released study, produced with help from eight universities, found some good news.

Between and , the global impact of human activities on the terrestrial environment is expanding more slowly than the rates of economic and/or population growth.

Environmental Impacts Of Large Dams Environmental Sciences Essay by admin on August 10, July 13, About big dikes have been built as a response to run into energy or H2O need.

History of Electricity - The oldest civilization known to understand electricity was the ancient Greeks because of the electric fish in the Nile River.

is and in to a was not you i of it the be he his but for are this that by on at they with which she or from had we will have an what been one if would who has her. Jul 18, · Environmental Sciences Obama Turns to Web to Illustrate the Effects of a Changing Climate This article discusses how the use of technology and the internet can aid in the overall global warming education process.

Leadership In Energy And Environmental Design Environmental Sciences Essay. by admin on September 6, July 13, The green edifice is portion of the construct sustainable buildings.

The demand of this type of edifices has increased in the last decennaries and it is expected to go on upward. LEED (Leadership in Energy and Environmental.